Switch Extensions::TabHelper to use WebContents, WebContentsUserData.

chrome/browser/ui/gtk/location_bar_view_gtk.cc

Index: chrome/browser/ui/gtk/location_bar_view_gtk.cc
diff --git a/chrome/browser/ui/gtk/location_bar_view_gtk.cc b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
index eb3ecdcb7004fff46a062ed380f023d6b90df326..b89f2a6dbbd95a039f600494db45ae532a2571db 100644
--- a/chrome/browser/ui/gtk/location_bar_view_gtk.cc
+++ b/chrome/browser/ui/gtk/location_bar_view_gtk.cc
@@ -956,10 +956,11 @@ void LocationBarViewGtk::UpdateContentSettingsIcons() {
 void LocationBarViewGtk::UpdatePageActions() {
   std::vector<ExtensionAction*> new_page_actions;
 
-  TabContents* tab_contents = GetTabContents();
-  if (tab_contents) {
+  WebContents* contents = GetWebContents();
+  if (contents) {
     LocationBarController* location_bar_controller =
-        tab_contents->extension_tab_helper()->location_bar_controller();
+        extensions::TabHelper::FromWebContents(contents)->
+            location_bar_controller();
     new_page_actions = location_bar_controller->GetCurrentActions();
   }
 
@@ -981,7 +982,6 @@ void LocationBarViewGtk::UpdatePageActions() {
         content::NotificationService::NoDetails());
   }
 
-  WebContents* contents = GetWebContents();
   if (!page_action_views_.empty() && contents) {
     GURL url = chrome::GetActiveWebContents(browser())->GetURL();
 
@@ -2036,7 +2036,8 @@ gboolean LocationBarViewGtk::PageActionViewGtk::OnButtonPressed(
     return TRUE;
 
   LocationBarController* controller =
-      tab_contents->extension_tab_helper()->location_bar_controller();
+      extensions::TabHelper::FromWebContents(tab_contents->web_contents())->
+          location_bar_controller();
 
   switch (controller->OnClicked(extension->id(), event->button)) {
     case LocationBarController::ACTION_NONE: